The present invention generally relates to a loading hopper for a ready mixed concrete truck, and more particularly to a loading hopper having a movable portion which eliminates restrictions during the off loading of concrete.
Ready mixed concrete trucks currently receive the various materials that make up concrete through an overhead delivery system. The truck is located under a delivery chute and the materials are loaded directly into a mixing drum on the truck. The materials are commonly directed into an opening in the mixing drum of the truck by a hopper located adjacent to the mixing drum. The hopper is generally a funnel shaped device extending into an open angularly raised portion of the mixing drum. The hopper is thus located to direct the downward pouring material directly into the angled mixing drum.
Concrete is provided in various mixes dependent upon the intended use. To form curbs, gutters, and the like, a thick concrete having a particularly high viscosity is normally employed. This type of concrete is commonly referred to as low slump concrete as it retains the shape in which it is poured. To form a curb the low slump concrete is dispensed from the mixing drum into a slipform machine. A slipform machine is a self-propelled, tracked machine, which continuously molds low slump concrete into various freestanding dimensions without the use of stationary forms. The ready mix concrete truck moves along with the slipform machine to discharge the concrete into the slipform machine.
Unfortunately, the thickness of the low slump concrete, which makes it so effective in the formation of curbs, creates particular difficulties during the dispensing process. The component materials and the concrete are commonly on loaded and off loaded from the mixing drum through the same opening in the mixing drum and thus the hopper is located adjacent the mixing drum opening. This is normally acceptable when using a concrete having a standard viscosity as the mixing drum opening and the hopper are spaced to allow passage of the concrete from the mixing drum to the dispensing apparatus. Nonetheless, the low slump concrete viscosity prevents effective off loading from the restricted area between the hopper and mixing drum opening, thus slowing down the unloading process.
When the low slump concrete becomes restricted during the off loading process, the truck cannot discharge at a rate comparable to the ability of the slipform machine. Due to this, the slipform machine has to be repeatedly stopped to allow the truck to catch up with product delivery. This disrupts the smooth continuous operation of the slipform machine resulting in an increase of manual repair to the finished product (curb, barrier wall etc.).
To avoid the restriction problem, another expedient solution is commonly performed. The entire traditional hopper assembly is commonly hinged to the mixing drum and can be raised by pneumatic or hydraulic cylinders during cleaning or maintenance. The entire hopper assembly is thus commonly raised during the off loading process to completely eliminate interference with the low slump concrete off loading (FIGS. 4A, 5A, and 6A prior art). However, commonly known hopper assemblies are manufactured as one-piece funnel shaped structures, which can weigh several hundred pounds. This creates the danger that the entire hopper assembly could fall if pneumatic or hydraulic pressure is lost and thus injure a closely located individual. In addition, when the hopper assembly is raised, the overall vehicle height is increased by up to three feet. The increased height thus prevents the truck from passing under standard clearance height objects such as bridges and power lines, which farther restricts the curb laying process.
The present invention provides a hopper assembly, which solves the above disadvantages while further improving the serviceability and effectiveness of a ready mixed concrete truck during the dispensing of low slump concrete.
The present invention also provides a hopper assembly having a main chute portion and a movable portion located adjacent to a storage container such as a ready mixed concrete truck mixing drum. The movable portion is attached to the main chute assembly and is moveable between an open position and a closed position, which corresponds to a material off loading position and a material on loading position, respectively.
The hopper assembly of the present invention further includes an actuator to move the movable portion between the material off loading position and the material on loading position. The actuator preferably is a pneumatic or hydraulic cylinder attached to the main chute portion which actuates the movable portion through a linkage assembly to move the movable portion between a closed position and the open position away from the mixing drum.
To provide the rapid on loading from an overhead delivery apparatus, the movable portion is moved to the material on loading position. The hopper assembly is therefore configured to direct material into an opening of the mixing drum. For the effective dispensing of high viscosity material such as low slump concrete the movable portion is moved to the off loading position. A passage area between the hopper assembly and the mixing drum is thereby increased and the restriction between the hopper assembly and the mixing drum is eliminated.